COVINA >> A dead crow has tested positive for West Nile Virus in unincorporated Covina, officials confirmed Wednesday. The bird was picked up Aug. 31 and tested positive for the virus, which already has killed one San Gabriel Valley man this month.

Four dead birds have been found in Covina, two in San Dimas and one each in Altadena, Glendora and Temple City, San Gabriel Valley Mosquito & Vector Control District spokesman Jason Farned said.

“There’s no cure and there’s no vaccine for West Nile Virus,” Farned said. “So the best precaution to take is prevention.”

Residents are encouraged to use repellents, wear long sleeves and pants if outdoors between dusk and dawn, ensure windows and doors are properly screened to keep mosquitoes out and eliminate sources of standing water, in which mosquitoes breed.

The San Gabriel Valley man who died was elderly, had pre-existing health conditions and was hospitalized in late August, according to county public health officials.

So far this year, 18 West Nile infections have been reported in Los Angeles County, officials said.